This is an open label, randomized, multiple dose study to quantify the amount of Nonoxynol-9 (N-9) retained in the vagina at selected timepoints after instillation. Five different formulations will be studied (foam, 2 types of gel, cellophane, and suppository). For each formulation studied, at least 4 timepoints of retention (2 hr, 4 hr, 8 hr, and 12 hrs) will be studied. For the AdvantageR gel formulation, a 24 hour timepoint will also be studied.